This article presents the computational optimization of a spark ignition engine fueled with biomass-derived syngas. KIVA 4 is used as simulation platform, where a three-dimensional model is implemented considering the valve system together with the intake and exhaust processes. For the optimization, a subroutine is developed that couples KIVA 4 with the nondominated sorting genetic algorithm II. Two optimization processes are performed, one at 2500 rpm and the other at 4500 rpm. In both cases, the aim is to optimize the equivalence ratio in the combustion chamber, with the objectives of maximizing the indicated thermal efficiency and minimizing the nitrogen monoxide emission. From the results, it can be deduced that the performance of the engine presents its optimum values for mixtures close to stoichiometry; however, these individuals also exhibit the highest nitrogen monoxide emissions. At both 2500 rpm and 4500 rpm, it was possible to find equivalence ratios that allow obtaining efficiencies greater than those achieved in the conventional operation of the engine, that is, when it is fueled with gasoline.